Radiation still high in fish near Fukushima

Oct. 26, 2012
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Three weeks after the March 11, 2001, earthquake and tsunami crippled the Fukushima Dai-ichi nuclear power plant, Japanese fishermen unloaded their catch at the nearby Hirakata fish market in Kitaibaraki, Ibaraki prefecture. Today, fish and seafood caught off the coast of the plant show radioactive cesium continues from either reactor leaks or seabed sediment. / Toru Yamanaka, AFP/Getty Images

by Michael Winter, USA TODAY

by Michael Winter, USA TODAY

Most fish and seafood caught near Japan's damaged Fukushima nuclear plant still have elevated levels of radioactive cesium more than 18 months after the March 2011 earthquake and tsunami, indicating continued contamination from either reactor leaks or seabed sediment, a U.S. researcher reports.

Nonetheless, the "vast majority" of fish caught off the northeast coast show radiation levels below tightened Japanese and international limits for seafood consumption, concludes marine chemist Ken Buesseler, of the Woods Hole Oceanographic Institution.

His analysis of data from the Japanese Ministry of Agriculture, Forestry and Fisheries was published Friday in the journal Science. He led an international team last year that studied the spread of radioactive elements from the Fukushima Dai-ichi plant.

"Although offshore waters are safe with respect to international standards for radionuclides in the ocean, the nuclear power plants continue to leak radioactive contaminants into the ocean," Buesseler says.

[T]he most highly contaminated fish continue to be caught off the coast of Fukushima Prefecture, as could be expected, and that demersal, or bottom-dwelling fish, consistently show the highest level of contamination by a radioactive isotope of cesium from the damaged nuclear power plant. He also points out that levels of contamination in almost all classifications of fish are not declining, although not all types of fish are showing the same levels, and some are not showing any appreciable contamination.

Buesseler found that 40% of bottom fish - cod, flounder, halibut, pollock, sole, greenlings and others - remain above the limit. Two greenlings caught in August contained cesium levels that were 250 times the level the government considers safe, the Associated Press notes.

Except for octopus and sea snails, the Japanese government has banned fish, other seafood and seaweed harvested near Fukushima from domestic markets or being exported.

Tokyo Electric Power Co. (TEPCO) has acknowledged that radioactive water used to cool the plant's damaged reactors leaked into the Pacific several times, most recently in April.

"Given the 30-year half-life of cesium-137, this means that even if these sources (of contamination) were to be shut off completely, the sediments would remain contaminated for decades to come," Buesseler wrote.

The study came as TEPCO said in its daily report that it had begun pumping contaminated water from the turbine room basement of Unit 3 to a radioactive-waste-treatment facility.